Although aneurysms, and particularly dissecting aortic aneurysms, refer to a state in which an ulceration has occurred in the tunica intima of the aorta, said tunica intima is partially ruptured, blood flows from that site inside the wall of the aorta and said aorta wall is dissected into two layers (the blood pathway that has formed between the blood vessel wall and said separated tunica intima is referred to as a “pseudo cavity”, while the space inside the tunica intima which is the inherent blood pathway is referred to as the “true cavity”), if this condition is left untreated, the outer wall of the aorta eventually ruptures leading to death.
The method for treating dissecting aortic aneurysms has conventionally only consisted of suturing and closing the ruptured portion of the above tunica intima (referred to as the “entry”, while the blood outlet of the “pseudo cavity” is referred to as the “reentry”) by surgery as an emergency procedure, or by excising the dissected blood vessel and replacing said excised portion with an artificial blood vessel.
However, in the above suturing and closing procedure, due to the fragile nature of the tissue around the entry, the suturing and closing procedure itself is extremely difficult. Moreover, even if suturing and closing procedure are successful and further risk is able to be avoided at least for the time being, there are many cases in which the patient dies within five years after surgery. On the other hand, in the case of replacing the dissected blood-vessel with an artificial blood vessel, the patient is subjected to considerable burden to the extensive nature of the procedure, and in the case the “pseudo cavity” is long, replacement with an artificial blood vessel cannot be applied since it ends up obstructing the furcation of blood vessels that branch from the aorta.
Recently, an appliance and method using that appliance have been reported as a non-surgical method in which a flexible, stretchable bag is attached to the end of a flexible catheter and expanded with a fluid injected from the base end of the catheter to form a hollow, cylindrical balloon. The balloon catheter, composed by laminating a plurality of hollow, tubular bodies, which are stretched by said stretchable bag due to said fluid, in the direction of the central axis around said stretchable bag, is inserted into the dissected portion of the tunica intima, and the tensile strength of said stretchable bag is then used to reduce said pseudo cavity, thereby allowing blood to flow to the true cavity (Japanese Patent No. 2546829). Although the method using this appliance is superior to methods of the prior art with respect to allowing closure of the entry in the acute phase while maintaining blood flow toward periphery, the fabrication of said hollow tubular body and its attachment to said stretchable bag are intricate and bothersome. Moreover, there is still room for further examination with respect to clinical application since, among other factors, there are limits on the degree to which the volume it occupies can be minimized when inserting into a blood vessel.